/*
 * Copyright 2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.security.kerberos.docs;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.FileSystemResource;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.config.annotation.web.servlet.configuration.EnableWebMvcSecurity;
import org.springframework.security.kerberos.authentication.KerberosAuthenticationProvider;
import org.springframework.security.kerberos.authentication.KerberosServiceAuthenticationProvider;
import org.springframework.security.kerberos.authentication.sun.SunJaasKerberosClient;
import org.springframework.security.kerberos.authentication.sun.SunJaasKerberosTicketValidator;
import org.springframework.security.kerberos.web.authentication.SpnegoAuthenticationProcessingFilter;
import org.springframework.security.kerberos.web.authentication.SpnegoEntryPoint;
import org.springframework.security.web.authentication.www.BasicAuthenticationFilter;

//tag::snippetA[]
@Configuration
@EnableWebMvcSecurity
public class SpnegoConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .exceptionHandling()
                .authenticationEntryPoint(spnegoEntryPoint())
                .and()
            .authorizeRequests()
                .antMatchers("/", "/home").permitAll()
                .anyRequest().authenticated()
                .and()
            .formLogin()
                .loginPage("/login").permitAll()
                .and()
            .logout()
                .permitAll()
                .and()
            .addFilterBefore(
                    spnegoAuthenticationProcessingFilter(authenticationManagerBean()),
                    BasicAuthenticationFilter.class);
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth)
    		throws Exception {
        auth
            .authenticationProvider(kerberosAuthenticationProvider())
            .authenticationProvider(kerberosServiceAuthenticationProvider());
    }

    @Bean
    public KerberosAuthenticationProvider kerberosAuthenticationProvider() {
        KerberosAuthenticationProvider provider =
        		new KerberosAuthenticationProvider();
        SunJaasKerberosClient client = new SunJaasKerberosClient();
        client.setDebug(true);
        provider.setKerberosClient(client);
        provider.setUserDetailsService(dummyUserDetailsService());
        return provider;
    }

    @Bean
    public SpnegoEntryPoint spnegoEntryPoint() {
        return new SpnegoEntryPoint("/login");
    }

    @Bean
    public SpnegoAuthenticationProcessingFilter spnegoAuthenticationProcessingFilter(
            AuthenticationManager authenticationManager) {
        SpnegoAuthenticationProcessingFilter filter =
        		new SpnegoAuthenticationProcessingFilter();
        filter.setAuthenticationManager(authenticationManager);
        return filter;
    }

    @Bean
    public KerberosServiceAuthenticationProvider kerberosServiceAuthenticationProvider() {
        KerberosServiceAuthenticationProvider provider =
        		new KerberosServiceAuthenticationProvider();
        provider.setTicketValidator(sunJaasKerberosTicketValidator());
        provider.setUserDetailsService(dummyUserDetailsService());
        return provider;
    }

    @Bean
    public SunJaasKerberosTicketValidator sunJaasKerberosTicketValidator() {
        SunJaasKerberosTicketValidator ticketValidator =
        		new SunJaasKerberosTicketValidator();
        ticketValidator.setServicePrincipal("HTTP/servicehost.example.org@EXAMPLE.ORG");
        ticketValidator.setKeyTabLocation(new FileSystemResource("/tmp/service.keytab"));
        ticketValidator.setDebug(true);
        return ticketValidator;
    }

    @Bean
    public DummyUserDetailsService dummyUserDetailsService() {
        return new DummyUserDetailsService();
    }

}
//end::snippetA[]
